Superhero movies are certainly not high cinema, but I challenge the "no risk" assertion. In the first 22 MCU films, the heroes take major losses in 5 films (e.g., a city is destroyed with impact affecting the rest of the series). The heroes suffer more personal losses in many other movies beyond those 5 (e.g., losing a loved one).
So you usually know what you will get, but the villain winning or partially winning is a credible threat.
I haven't watched all the movies (or even the majority?) but cities getting trashed while fighting has definitely become a meme. It never feels like there are any ramifications, you never see people actually get hurt even when huge skyscrapers collapse in the middle of the street. If there was an impact for the rest of the series, I haven't noticed, but the destruction scenes just feel like none of it has any weight or meaning besides the cool CGI. Passing mentions about an attack on NYC is not showing the actual consequences of these events.
The "major losses" always felt like they are manifactured in a shallow and meaningless way. You know your heroes aren't going to lose, or die, or get too badly injured. They will always bounce back and the damage will be reversed.
And this is all fine given you accept that superhero movies are primarily entertainment for kids. Which by the way explains why we get the same reboots and origin stories every 10-15 years for a fresh batch of kids.
Of course it's a matter of taste but I just don't see any substance in these movies. Honestly even when I was a kid myself I never really saw the appeal in something like "Batman vs Superman" or "Godzilla vs King Kong". It always seemed pointless to me. As an adult I am just puzzled trying to understand how these movies can hold anyone's attention. But to each their own I guess.
I have no choice but to wholly agree with Scorsese. Unengaging, predictable, day care in a theater.
One frustrating thing about Marvel properties is they frequently almost have a point or address their own messes or even something important in the real world—but then pull back before actually saying anything. A couple of the Spider Man movies have done this, Falcon and Winter Soldier had a bad case of this, a few of the other films (Black Panther comes to mind—a riskier version of that film with a somewhat shifted perspective and a bit more bite could have been amazing). Most just don't even try to take a stance on anything whatsoever, but sometimes they start to and it's like "oh man is this going to be actually good instead of just good-for-a-Marvel-movie good?" but... no, never.
So you usually know what you will get, but the villain winning or partially winning is a credible threat.